Leaving power tools, especially those with lithium-ion batteries, in your car can be a safety concern. While high-quality batteries from reputable brands undergo rigorous testing and have safety features, extreme temperatures and potential hazards make it unwise to store them in your vehicle long-term. This article explores the risks and provides recommendations for safe power tool battery storage.
Heat and Battery Longevity
High temperatures inside a parked car, especially during summer, can accelerate battery degradation. While lithium-ion batteries are designed to withstand high temperatures (up to 158°F), prolonged exposure to extreme heat can significantly shorten their lifespan, reduce their capacity, and diminish their ability to deliver high power output. This degradation is primarily a concern for longevity rather than immediate safety. Samsung, for example, tests its batteries at 266°F for 10 minutes to ensure they can withstand extreme conditions before critical failure.
Potential Fire Risks and Battery Defects
While rare, defective batteries can pose a fire risk. Poor quality or damaged batteries might be more susceptible to thermal runaway, a chain reaction that can lead to overheating and fire. Reputable brands have significantly lower defect rates due to stricter quality control, but the risk is never zero. Removing batteries from tools and chargers when not in use minimizes the risk of overdischarge, which can also create a fire hazard when the battery is recharged.
Best Practices for Power Tool Battery Storage
For optimal safety and battery longevity, it’s best to:
- Remove batteries from tools and chargers: This eliminates potential standby drain, which can lead to deep discharge and potential fire hazards.
- Store batteries in a cool, dry place: Avoid storing batteries in direct sunlight or hot environments like a car trunk or shed. A climate-controlled environment is ideal.
- Keep batteries away from flammable materials: Store batteries separate from paper, wood, or other easily ignitable substances.
- Store batteries at a lower state of charge: A lower charge level (around 30-60%) can prolong battery life and potentially reduce the severity of a thermal runaway event. Don’t recharge batteries immediately after use unless necessary.
Comparing Power Tool Batteries to Laptop Batteries
Laptop batteries also use lithium-ion technology, so similar safety concerns apply. However, the cumulative risk increases with the number and size of batteries. While the risk of a single laptop battery fire is relatively low, storing numerous large power tool batteries in a confined space like a car significantly increases the potential consequences of a battery failure.
The Aviation Industry’s Perspective on Battery Safety
The aviation industry has extensively researched lithium-ion battery safety. Their findings indicate that the energy released during a thermal runaway decreases with the battery’s state of charge. Regulations now mandate that batteries shipped as air cargo be charged to no more than 30% to mitigate potential in-flight fires.
Conclusion
While not inherently dangerous, leaving power tool batteries in your car increases the risk of damage and potential fire hazards. By following recommended storage practices, you can significantly reduce these risks and extend the life of your batteries. Removing batteries from tools and chargers, storing them in a cool environment away from flammable materials, and maintaining a lower state of charge are simple yet effective ways to ensure safety and maximize battery performance. Prioritize proper battery care for both safety and long-term cost savings.
